The structure of nicotine is as follows:
In the aromatic ring, nitrogen atom has two bonds and one lone pair therefore, hybridization will be [tex]sp^{2}[/tex]. In five-membered ring , nitrogen has two bonds and 1 lone pair therefore, hybridization will be [tex]sp^{3}[/tex].
Therefore, hybridization state of [tex]N^{1}[/tex] and [tex]N^{2}[/tex] (as in the attached structure) is [tex]sp^{2}[/tex] and [tex]sp^{3}[/tex] respectively.
Now, according to VESPR theory for [tex]sp^{2}[/tex] hybridization with one lone pair the geometry is bent and for [tex]sp^{3}[/tex] hybridization with one lone pair the geometry is pyramidal.
Therefore, geometry of [tex]N^{1}[/tex] and [tex]N^{2}[/tex] (as in the attached structure) is bent and pyramidal respectively.
